DEVICE OF QUANTUM DISTRIBUTION OF CRYPTOGRAPHIC KEY ON MODULATED RADIATION FREQUENCY SUBCARRIER Russian patent published in 2012 - IPC H04L9/08 

FIELD: information technologies.

SUBSTANCE: device for quantum distribution of a key on subcarrier frequencies of modulated radiation differs by the fact that in a receiving device an electric optic phase modulator in a receiving device is made of two electric optic phase modulators arranged along with radiation, control inputs of which are connected with the first and second output of a phase shift device accordingly, besides, the output of the first electric optic phase modulator is optically coupled with the output of the second electric optic phase modulator, downstream the modulators along with radiation there is a faraday mirror optically coupled with an input of the second electric optic phase modulator, and also an optical circulator is introduced, the first port of which is optically coupled with a fibre optic communication line, the second port is optically coupled with an input of the first electric optic phase modulator, the third port is optically coupled with a spectral filter, and the fourth port is optically coupled with an input of a single photon receiver, a synchronisation device has the third and fourth outputs, which are connected with synchronisation inputs of phase shift devices in receiving and transmitting devices accordingly.

EFFECT: reduced coefficient of quantum errors, higher speed of transfer and increased extent of cryptographic key protection.

2 dwg